4. quiver. 5. Waver,fluctuate,vacillate refer to an alternation or hesitation between one direction and another. Waver means to hesitate between choices: to waver between two courses of action.Fluctuate suggests irregular change from one side to the other or up and down: The prices of stocks fluctuate when there is bad news followed by good.Vacillate is to make up one's mind and change it again suddenly; to be undecided as to what to do: We must not vacillate but must set a day.

waver

v.

late 13c., weyveren, "to show indecision," probably related to Old English wæfre "restless, wavering," from Proto-Germanic *wæbraz (cf. Middle High German wabern "to waver," Old Norse vafra "to hover about"), a frequentative form from the root of wave (v.). Related: Wavered; wavering.